Conventionally, a vehicle such as a hybrid vehicle, an electric vehicle and a fuel cell vehicle using an electric motor as a driving source has been known. Such a vehicle is equipped with a power storage device (energy storage device) such as a battery in order to store electric power to be supplied to the electric motor. Electric power generated during regenerative braking and electric power generated by a generator mounted on the vehicle are stored in the battery.
Recently, in the vehicle as described above, a configuration has been proposed in which the power storage device is charged by a power supply external to the vehicle (that will also be simply referred to as “external power supply” hereinafter) such as a household power supply. Specifically, an outlet provided at a house is coupled to a connector provided on the vehicle by a cable, so that the power storage device (battery) of the vehicle is charged with electric power supplied from the household power supply. The vehicle in which the power storage device such as the battery mounted on the vehicle can be charged by the power supply external to the vehicle will also be referred to as “plug-in vehicle” hereinafter.
The standard for the plug-in vehicle is defined by “Electric Vehicle Conductive Charging System, General Requirements” (Non-Patent Document 1) in Japan, and by “SAE Electric Vehicle Conductive Charge Coupler” (Non-Patent Document 2) in the United States of America.
In such a plug-in vehicle, it has been proposed to operate an electric air conditioner at the time of charging by the external power supply (that will also be referred to as “external charging” hereinafter) and carry out pre-air-conditioning such as preheating or precooling during which the vehicle interior is air-conditioned in advance before the vehicle starts to travel (for example, Patent Documents 1 to 4). As a result of such pre-air-conditioning, the vehicle interior has already been air-conditioned when the vehicle starts to travel. Therefore, the electric power consumed for air conditioning while the vehicle is traveling is suppressed. Thus, the electric power of the power storage device used for traveling of the vehicle can be maximized.
For example, Japanese Patent Laying-Open No. 8-65814 (Patent Document 1) and Japanese Patent Laying-Open No. 8-65815 (Patent Document 2) disclose a charging control apparatus for an electric vehicle in which electric power supplied from an external power supply is divided into electric power to be consumed by an electric air conditioner and a charging current of a vehicle-mounted battery of the electric vehicle at the time of external charging of the battery.
In particular, Patent Document 1 discloses charging control for carrying out pre-air-conditioning while giving priority to charging of the battery at the time of external charging. On the other hand, Patent Document 2 discloses charging control in which, at the time of external charging, when an instruction for preferentially operating the electric air conditioner is generated, electric power that allows the electric air conditioner to be operated until rated electric power is reached is allocated to the electric air conditioner, and the battery is charged with the remaining electric power.
Furthermore, Japanese Patent Laying-Open No. 2001-63347 (Patent Document 3) discloses an air-conditioning control system for a vehicle in which electric power supplied from an external power supply is used to operate a pre-air-conditioning device at the time of external charging, and in addition, the vehicle interior can also be preliminarily cooled or heated after the external charging is canceled. Specifically, electric power supplied from a secondary battery is used to operate the pre-air-conditioning device, for a certain period of time from when the external power supply is removed from the vehicle after the external charging ends to when an occupant climbs into the vehicle and the vehicle is ready to operate.
In addition, Japanese Patent Laying-Open No. 2000-78701 (Patent Document 4) discloses an air-conditioning device for an electric vehicle configured to select the air-conditioning capacity in accordance with charging power (charging voltage level) when pre-air-conditioning is carried out at the time of external charging, and thereby, carry out pre-air-conditioning without consuming electric power of a battery even if the charging power is small.    Patent Document 1: Japanese Patent Laying-Open No. 8-65814    Patent Document 2: Japanese Patent Laying-Open No. 8-65815    Patent Document 3: Japanese Patent Laying-Open No. 2001-63347    Patent Document 4: Japanese Patent Laying-Open No. 2000-78701    Non-Patent Document 1: “Electric Vehicle Conductive Charging System, General Requirements,” Japan Electric Vehicle Association Standard (Japan Electric Vehicle Standard), Mar. 29, 2001    Non-Patent Document 2: “SAE Electric Vehicle Conductive Charge Coupler,” (United States of America), SAE Standards, SAE International, November, 2001